Grinding wheel dresser

ABSTRACT

Apparatus for dressing a grinding wheel includes a bit holder carriage which is reciprocably driven to move a bit across the working face of the wheel, the bit being carried by a member which is rotated in the holder after every other traverse of the wheel thereby changing the working edge of the bit and advancing it toward the wheel.

United States Patent 11 1 Sollami 1 Mar. 11, 1975 GRINDING WHEELDRESSER2,862,492 12/1958 Bruce 125/11 N 2,909,006 10 1959 B1 d 125 11 N X [76]Inventor: Phillip A. Sollami, 438 Sherman $1., I

Downers Grove 111 0515 FOREIGN PATENTS OR APPLICATIONS Filed Nov 5 1973581,487 8/1959 Canada 125/11 PH [21] Appl. No.1 412,709 PrimaryE.raminerHarold D. Whitehead Attorney, Agent, or FirmEdmond T. Patnaude[52] US. Cl ..125/1l TP 151 1111. C1 B24b 53/08 [571 3 158] Field ofSearch 125/11 R, 11 N, 11 TP, Apparatus for dressmg a grmdmg WheelIncludes a bit 25 1 p 1 1 CC holder carriage which is reciprocablydriven to move a bit across the working face of the wheel, the bit being5 References Cited carried by a member which is rotated in the holderUNITED STATES PATENTS after every other traverse 0f the wheel therebychanging the working edge of the bit and advancing it to- 2,611,3569/1952 Flygare 125/11 TP Ward the Wheel 2,630,109 3/1953 Bruce 125/11 N2,648,171 8/1953 H111 125/11 N 8 Claims, 4 Drawing Figures GRINDINGWHEEL DRESSER The present invention generally relates to the art ofdressing grinding wheels, and it relates more particularly to a new andimproved machine for automatically dressing the working surface of thegrinding wheel to a predetermined contour.

Apparatus which automatically dresses a grinding wheel is not basicallynew, but the prior art wheel dressers have been expensive to manufactureand maintain, require a time consuming set up operation, requirerelatively skilled operators, and require frequent replacement of thedressing bit. There is, therefore, a need for a better wheel dresserwhich is stable in operation and avoids excessive wear on the dressingbit, which is relatively inexpensive to manufacture, and which can beused by relatively unskilled operators.

Therefore, a principal object of the present invention is to provide newand improved apparatus for dressing the working surfaceof a grindingwheel to a desired contour.

Another object of this invention is to provide a new and improvedmechanism for converting rotary motion to reciprocatory motion.

A further object of this invention is to provide a new and improved feedmechanism for automatically feeding and rotating a dressing bit a presetamount.

SUMMARY OF THE INVENTION Briefly, the above and further objects may berealized in accordance with a preferred embodiment of the presentinvention by providing an electric motor driven translatory mechanismcarrying a longitudinally movable bit holder which follows the contourof a template and which is automatically rotated and advanced apredetermined amount after every other pass across the working surfaceof a grinding wheel being dressed.

BRIEF DESCRIPTION OF THE DRAWINGS Further objects and advantages and abetter understanding of the present invention can be had by refer enceto the following detailed description. wherein:

FIG. 1 is an elevational view of a grinding wheel dresser embodying thepresent invention;

FIG. 2 is a vertical section of the machine of FIG. 1 taken along theline 202 thereof;

FIG. 3 is another sectional view taken along the line 3-3 of FIG. I; and

FIG. 4 is a sectional view taken along the line 44 of FIG. Iparticularly showing the automatic bit feed or advance mechanism.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings andparticularly to FIGS. 1 and 2 thereof, awheel dressing machine includesa base plate 11 suitably mounted in fixed relationship with respect to agrinding wheel 12 to be dressed. A mounting plate 13 is fixed to andextends upwardly from the base plate 11 to support two sets of pillowblocks 15 and 16 respectively mounting a pair of roller or slidebushings 1-7 and 18. A guide rod 21 is slidably supported in the lowerbushings 18 in precise parallel relationship with the upper rod 21.. Thebushings l7 and 18 are preferably super ball bushings manu factured byThomson Industries, Inc.. wherein preload on the rods is proportional tothe compressive force exerted on the bushings by the pillow blocks. Theblocks 15 and 16 arethus held together by a plurality of set screws 23which are used to adjust thecompressive force on the bushings 17 and 18and thus preload on the guide rods.

A tool holder carriage 25 includes a tubular portion 26 from which apair of spaced apart arms 27 "and 28 extend in a rearward directionthrough a pair of horizontal slots 29 and 30 in the'mounting plate 13.The rods 21 and 22 extend through suitable holes in the arms 27 and 28and are fixed thereto by any suitable means so as to be carried by andto move in unison with the rods 21 and 22. A drive member 33 having arearwardly facing drive channel 34 is secured by bolts to the rear facesof the arms 27 and 28 and a roller 35 is disposed in the channel 34. Theroller 35 is connected by a threaded stud 36 and a nut 37 to a crank arm38 which is rotatably driven by the output shaft 39 of an electric motorand gear reduction unit 40. As thus far described it may be seen thatenergizing the drive motor rotates the crank arm 38 and the roller 35 toreciprocably drive the bit holder in a horizontal direction with therods 21 and 22 reciprocating back and forth in the bushings 17 and 18.

Referring particularly to FIG. 3 it may be seen that the forward portion26 of the tool holder is generally tubular and has an axial bore thereinhaving a lower portion 43 and an upper portion 44 of reduced diameter. Asliding fit is provided between a cylindrical rod 45 and the boreportion 43 in which it is located. The upper portion of an axial bore 46provided in the rod 45 is threaded to receive the threaded shank 47 ofan advance screw having a cylindrical guide portion 48 at the top. Theguide portion 48 is slidably received in the upper bore portion 44, anda coil spring 51 is compressed between the upper end of the advancescrew and a disc 52 held in place in the upper end ofthe bore portion 44on a rocker pin 53. The spring 51 thus biases the advance screw and therod 45 to which it is connected in a downward direction relative to thebit holder.

In order to cause the advance screw and rod to follow a predeterminedcontour or pattern as the bit holder reciprocates back and forth in thebushings 17 and 18, a template follower includes a follower pin 56having an internally threaded body portion 57 attached to the guideportion 48 by means of a socket head screw 58 threadedly received in thebody portion 57. A ball bearing roller 59 is mounted on the body portion57 and held in place by a snap ring 60 and rides in a vertical slot 62milled in the wall of the tool holder tube 26 to permit up and downmovement of the template follower while preventing roatation of theadvance screw in the bit holder. As best shown in FIGS. 1 and 2 thefollower sleeve 56 rides on the upper edge 63 of a tem plate plate 64fastened to the mounting block 65 by a plurality of screws 66. The upperedge 63 of the template is provided with the desired cross-sectionalcontour of the wheel to be dressed. The template 64 can, of course, bereadily replaced with others having different contours or profiles. Apair of adjustment screws 67 are threadedly received in the lip of theblock 65 for adjustment of the template in the vertical plane.

A wheel dressing bit 68 having a diamond or other cutting tip 69 securedin the lower end thereof is supported in the lower end of the rod 45 andheld firmly in place therein by means of a set screw 70 threadedlyreceived in a knurled collar 73 slipped or sweated onto the lower end ofthe rod 45. Another collar 71 is threaded onto the lower end of the bitholder portion 26 and has an internal groove receiving a scraper ring 72which is slightly compressed against the rod 45 to prevent spuriousrotation thereof and to provide a protectiveseal for the interengagingsliding surfaces of the rod 45 and the bore 43.

i In order to advance the dressing bit an adjustable predeterminedamount after every other tranverse of the wheel, an advance lever 75 ispivotally carried on a pintle 81 by a split ring 76 mounted in a pair ofslots 77' and 78 in the tubular portion 26. The ring 76 has an arcuateinnersurface 79 which rides on the CD. of the rod 45, an the advancelever 75 extends through a slot 80 in the ring 76 for driving engagementwith the rod 45 as best shown in FIG.,4. The inner end 83 of the lever75 is cut on a bias so as to drivingly engage the rod 45 when the leveris pivoted in a clockwise direction as shown in FIG. 4. Near the end ofits leftward stroke as shown in FIGS. 1 and 4, the bit holder carriesthe lever 75 into engagement with a screw 85 adjustably mounted by abracket 86 to the plate 13. The lever 75 is thus pivoted in theclockwise direction causing the end 83 to engage and lock against therod 45. Further movement of the carriage causes the ring 76 to rotateand the rod 45 to rotate therewith relative to the advance screw 47which is prevented from rotating by the roller 59 disposed in the slot62, whereby the rod 45 is screwed downwardly on the advance screw toadvance the dresser bit 69 toward the axis of rotation of the grindingwheel 12 and to rotate the bit 69 a small predetermined amount. Thedistance through which the bit is advanced and the angle through whichit is rotated is controlled by the distance between the end of the screw85 and the end of the stroke of the bit holder and is adjustable byvarying the position of the screw 85 in the bracket 86. As the bitholder moves back in the opposite direction during the succeeding stroketo carry the lever 75 away from the screw 85, the ring 76 and the lever75 are returned to the illustrated cocked position by means ofa coilspring 88 stretched between apost 89 on the ring 76 and a stud 90 on thebit holder 26. At this time the inner end 83 of the lever 75 pivots awayfrom and slides loosely across the surface of the rod 45 which isprevented from rotating by the scraper ring'72 and the relatively tightfit between the mating threads on the advance screw 47 and the rod 45.

If desired a second advance lever may be carried by the ring 76 at alocation opposite the lever 75 and a second screw and bracket is mountedat the right side of plate 13 as viewed in FIG. 1 to advance the bit atthe end of each stroke of the carriage ratherthan on every other stroke.

One problem commonly encountered with wheel dressers is that theabrasive dust removed from the wheel by the dressing bit finds its wayinto the moving parts of the machine. To shield the moving parts of themachine from this dust, a housing, partially shown at 93, encloses theparts of the machine between the plates 11 and 13, and caps (not shown)mounted to the housing are positioned over both ends of the rods 21 and22. Adjacent to a horizontal slot 94 in the base plate 11 in which thebit holder reciprocates, a pair of undercut guide pieces 95 and 96 aremounted to the plate and a rectangular dust shield 97 is slidabletherein.

' The shield may conveniently be formed of plastic and is provided witha hole 98 through which the lower cy-" lindrical portion of the bitholder tightly extends. The shield 97 thus slides back and forth in thechannel formed by the strips 95 and 96 and the bottom surface of theplate 11 to prevent foreign matter from entering the housing 93.

OPERATION In use, the machine 10 is mounted directly above the grindingwheel 12 to be dressed with the bit 69 located directly over the axis ofthe rotation of the wheel. The proper template 64 is mounted in placeand the knurled collar 73 is rotated to lower the bit into nearengagement with the grinding wheel. With the wheel rotating at normalspeed, the motor 40 is then started to cause the bit to reciprocate backand forth across the working surface of the wheel. Near the end of eachleftward stroke the rod 45 is rotated a small preset amount by the leverto advance the bit downwardly a cone sponding amount and also to rotatethe bit. As a result of the intermittent rotation of the bit and thefact that it cuts first in one direction and then in the otherdirection, the entire surface of the bit is used thereby providingextemely long bit life. Moreover, the substantial spacing between thebushing 17 and 18 and between the rods 21 and 22 maintains the bitholder in precise alignment so that no uncontrolled movement of thebrittle bit with a consequent fracturing thereof occurs.

When a template is to be changed, the tool holder carriage is positionedbetween the template mounting screws 66, the tool holder is elevated toraise the template follower away from the template, and the template isremoved-and replaced. The tool holder is then permitted to movedownwardly whereby the follower engages the upper edge of the newtemplate. The tool holder can then be rotated to accommodate thediameter of the new wheel. Also, the template can be adjusted laterallyto match the width of the new wheel.

While the present invention has been described in connection withparticular embodiments thereof, it will be understood by those skilledin the art that many changes and modifications may be made withoutdeparting from the true spirit and scope ofthe present invention.Therefore, it is intended by the appended claims to cover all suchchanges and modifications which come within the true spirit and scope ofthis invention.

I claim:

1. Apparatus for use in dressing the peripheral working surface of agrinding wheel to a predetermined contour, comprising a base memberadapted to be mounted in fixed rela tionship to the axis of rotation ofa grinding wheel to be dressed,

a tool holder carriage,

means mounting said carriage for reciprocable movement along arectilinear path parallel to said axis of rotation of said grindingwheel,

motor means for driving said carriage back and forth along said path,

a dressing bit holding member carried by said carriage for guidedmovement in a direction perpendicular to said path,

an advance screw being carried by said carriage and held againstrotation relative thereto,

a template mounted to said base member.

a template follower connected to said advance screw.

and

means carried by said bit holder carriage and intermittently operated inresponse to the reciprocation of said holder relative to said basemember for intermittently rotating said bit holding member relative tosaid advance screw to intermittently advance said bit holding member andto rotate said dressing bit.

2. Apparatus according to claim 1 wherein said tool holder carriage isprovided with a bore,

. said dressing bit holding member and said advance screw being disposedin said bore.

3. Apparatus according to claim 2 further comprising spring meansmounted between said tool holder carriage and said advance screw forurging said template follower against said template.

4. Apparatus according to claim 2 wherein said means for intermittentlyrotating said bit holding member comprises a first member mounted tosaid holder for limited rotational movement,

a drive lever pivotally mounted to said first member with one endadapted to engage and rotate said bit holding member when said lever ispivoted in a first direction only, and

adjustable means carried by said base member for engagement by saidlever to pivot said lever in said first direction and to rotate saidfirst member as said lever is moved relative thereto during thereciprocation of said holder.

5. Apparatus according to claim 4 comprising spring means mountedbetween said holder and said first member for urging said first memberin a di rection opposite to the direction of rotation caused by saidadjustable means.

6. Apparatus according to claim 1 wherein said means mounting said toolholder comprises a plurality of parallel rods fixedly connected to saidtool holder, and

a plurality of sets of bearings slidably supporting said rods.

7. Apparatus according to claim 6 wherein said means for intermittentlyrotating said bit holding member comprises a first member mounted tosaid holder for limited rotational movement,

a drive lever pivotally mounted to said first member with one endadapted to engage and rotate said bit holding member when said lever ispivoted in a first direction only, and

means carried by said base member for engagement by said lever to pivotsaid lever in said first direction thereby to rotate said bit holdingmember relative to said advance screw and said bit holder.

8. For use with grinding apparatus the combination comprising a mountingmember,

a plurality of sets of slide bearings fixed to said mounting member, thebearings in each set being arranged in mutually aligned relationshipwith said sets being arranged in mutually parallel relationship aplurality of rods respectively positioned in said sets of bearings,

a tool holder carriage fixed to said rods,

means for reciprocatively driving said carriage and said rods back andforth in said bearings,

said mounting member being provided with at least one openingtherethrough,

a portion of said carriage extending through said opening,

a guide channel connected to said carriage and disposed on the side ofsaid member opposite to said rods,

a crank arm having a drive portion slidably disposed in said guidechannel, and

motor means drivingly connected to said crank arm.

1. Apparatus for use in dressing the peripheral working surface of agrinding wheel to a predetermined contour, comprising a base memberadapted to be mounted in fixed relationship to the axis of rotation of agrinding wheel to be dressed, a tool holder carriage, means mountingsaid carriage for reciprocable movement along a rectilinear pathparallel to said axis of rotation of said grinding wheel, motor meansfor driving said carriage back and forth along said path, a dressing bitholding member carried by said carriage for guided movement in adirection perpendicular to said path, an advance screw being carried bysaid carriage and held against rotation relative thereto, a templatemounted to said base member, a template follower connected to saidadvance screw, and means carried by said bit holder carriage andintermittently operated in response to the reciprocation of said holderrelative to said base member for intermittently rotating said bitholding member relative to said advance screw to intermittently advancesaid bit holding member and to rotate said dressing bit.
 1. Apparatusfor use in dressing the peripheral working surface of a grinding wheelto a predetermined contour, comprising a base member adapted to bemounted in fixed relationship to the axis of rotation of a grindingwheel to be dressed, a tool holder carriage, means mounting saidcarriage for reciprocable movement along a rectilinear path parallel tosaid axis of rotation of said grinding wheel, motor means for drivingsaid carriage back and forth along said path, a dressing bit holdingmember carried by said carriage for guided movement in a directionperpendicular to said path, an advance screw being carried by saidcarriage and held against rotation relative thereto, a template mountedto said base member, a template follower connected to said advancescrew, and means carried by said bit holder carriage and intermittentlyoperated in response to the reciprocation of said holder relative tosaid base member for intermittently rotating said bit holding memberrelative to said advance screw to intermittently advance said bitholding member and to rotate said dressing bit.
 2. Apparatus accordingto claim 1 wherein said tool holder carriage is provided with a bore,said dressing bit holding member and said advance screw being disposedin said bore.
 3. Apparatus according to claim 2 further comprisingspring means mounted between said tool holder carriage and said advancescrew for urging said template follower against said template. 4.Apparatus according to claim 2 wherein said means for intermittentlyrotating said bit holding member comprises a first member mounted tosaid holder for limited rotational movement, a drive lever pivotallymounted to said first member with one end adapted to engage and rotatesaid bit holding member when said lever is pivoted in a first directiononly, and adjustable means carried by said base member for engagement bysaid lever to pivot said lever in said first direction and to rotatesaid first member as said lever is moved relative thereto during thereciprocation of said holder.
 5. Apparatus according to claim 4comprising spring means mounted between said holder and said firstmember for urging said first member in a direction opposite to thedirection of rotation caused by said adjustable means.
 6. Apparatusaccording to claim 1 wherein said means mounting said tool holdercomprises a plurality of parallel rods fixedly connected to said toolholder, and a plurality of sets of bearings slidably supporting saidrods.
 7. Apparatus according to claim 6 wherein said means forintermitteNtly rotating said bit holding member comprises a first membermounted to said holder for limited rotational movement, a drive leverpivotally mounted to said first member with one end adapted to engageand rotate said bit holding member when said lever is pivoted in a firstdirection only, and means carried by said base member for engagement bysaid lever to pivot said lever in said first direction thereby to rotatesaid bit holding member relative to said advance screw and said bitholder.